Mp_api module import issue

My python code generates an error at the very first import command “from mp_api.client import MPRester” that “No module named ‘bson.tz_util’”

What’s odd is that it initially worked without a problem but later I pip-installed bson it stopped working. I later pip-uninstalled bson and reinstalled mp_api, but none of these can resolve this issue now.

it got resolved by uninstalling pymongo and reinstalling mp_api.